Hi Folks

We are developing a streaming system which uses MediaRecorder with timeslice.

It's clear that Safari only has MediaRecorder as developer experiment, and that older versions of Safari dont support timeslice anyway.

However, a recent WebKit thread https://bugs.webkit.org/show_bug.cgi?id=202233

Suggests that timeslice *is* implemented in Safari 14.0.2 and the author provided an example jsfiddle: https://jsfiddle.net/hdwc2xzL/

Our experience suggests all is not as expected:

On Big Sur (on Apple DTK)

- Safari 14.02 (with mediarecorder enabled in experimental features) does appear to work as expected. MediaRecorder and timeslice all correct.

On macOS Mojave (on MacBook Pro intel)

- Safari 13 - (with mediarecorder enabled in experimental features). MediaRecorder initialises OK and works as expected (but without timeslice callbacks)

- Safari 14.0.2 (with mediarecorder enabled in experimental features) Throws an error when initialising MediaRecorder "NotSupportedError: The MediaRecorder is unsupported on this platform”

Both our own mechanism. and the jsfiddle referenced above shows the same error;

try

{

mediaRecorder = new MediaRecorder(window.stream, options); // options is just {videoBitsPerSecond: 1500000} - hence allowing default mimetype, window.stream successful from getUserMedia

}

catch (e)

{

console.error('navigator.getUserMedia error:', e);

errorMsgElement.innerHTML = `navigator.getUserMedia error:${e.toString()}`;

// fails: "NotSupportedError: The MediaRecorder is unsupported on this platform”

}

so we dont even get as far as calling mediaRecorder.start(timeslice_ms) any more (as we did with Safari 13)

Could anyone explain this behaviour in Mojave ?

Should MediaRecorder work on the official shipping 14.02 downloaded on Mojave ?

On a related note - what should we expect from mobile Safari with respect to timeslice MediaRecorder ?

When might we see MediaRecorder enabled by default so we can use it for customer applications ???

Many Thanks !